Perhaps you should try some spelling variations:
hang viet » hoang viet, nang viet, mang viet
luc nganh » chuc nganh, luat nganh, luc canh
cau tren » cu tren, dau tren, ca tren
viet cau » viet chau, viet ca, viet chu
luc ngan » luc nhan, luat ngan, vu ngan
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ty hang » ly hang, ty xang, thi hang
ly nang » ky nang, ly hang, ly vang
ve cau » ke cau, va cau, ve cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((ly nang) or (ty hang)) xa hoi. hieu ve cau ((luc ngan) or (luc nganh)) hang viet cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ly nang) OR (ty hang)) xa hoi. hieu ve cau ((luc ngan) OR (luc nganh)) hang viet cau tren.
• Adding a wildcard symbol may retrieve word variants: su sach ((ly nang) or (ty hang)) xa hoi. hieu ve cau ((luc ngan) or (luc nganh)) hang viet cau tren*.